Katy Reverse Osmosis

Reverse Osmosis Systems in Katy

Drinking Water You Like, Right at the Kitchen Tap

If you carry cases of bottled water home from the store, or keep a pitcher filter in the fridge that never seems to keep up, an under-sink reverse osmosis (RO) system can replace both. It fits in the cabinet under the kitchen sink, fills a small storage tank, and serves very low-mineral water from its own faucet for drinking, coffee and cooking.

RO works by pushing water through a membrane fine enough to hold back most dissolved minerals and many other substances, with carbon filters before and after it. It serves one faucet, not the whole house. In Katy, the part that deserves the most thought is the pre-filtration, because the water arriving at your sink depends on your district and whether it has switched to chloramine.

To talk about drinking water for your Katy home, call 281-979-3405.

Chloramine Conversions and Your RO Pre-Filters

Many Katy-area districts blend in treated surface water from the North Fort Bend Water Authority, which says all surface water in Fort Bend County is treated with chloramine. In 2026, Cinco MUD 5, 7 and 14 posted notices of conversion from chlorine to chloramines, taking effect on or after June 30, 2026. The City of Katy's own system reported free chlorine in 2025.

That matters for RO because the membrane is not a reliable barrier to chloramine, and chlorine compounds can damage common membranes. The carbon pre-filters do that job, so on chloraminated water they need to be suited to chloramine, sized for contact time and changed on schedule. Chloramine can use up ordinary carbon faster than free chlorine does.

If your RO system was installed before your district converted, its pre-filters may not be the right type, or the old replacement schedule may be too long. We can check what you have. For the background, see chloramine removal and the Katy water systems table.

Hardness and the Membrane

Katy-area water runs from moderately hard to hard in most state samples; the City of Katy's ranged from 6.4 to 9.1 grains per gallon between January 2025 and April 2026. Hardness minerals can scale an RO membrane over time. Homes with a water softener feed the RO softened water, which is easier on the membrane. Without one, we take your hardness into account when choosing the system and the maintenance schedule.

PFAS, Lead and Fluoride

These are the three questions we hear most about drinking water. Here is where each stands, and what an RO system can and can't do.

PFAS. In 2024, the U.S. Environmental Protection Agency set drinking water limits of 4.0 parts per trillion for PFOA and PFOS, plus limits for several other PFAS. In May 2026, EPA proposed keeping the PFOA and PFOS limits, with a possible extension of the compliance date to 2031, and rescinding the limits for the others. Check EPA's PFAS page for the current status. RO systems can be certified under NSF/ANSI 58 for PFOA and PFOS reduction. More on our PFAS removal page.

Lead. EPA says lead gets into drinking water when plumbing materials that contain lead corrode, and that the most common sources are lead pipes, faucets and fixtures. Your district's report covers the water it delivers, not your home's plumbing. If you use a filter for lead, EPA advises one certified to reduce it. See lead removal.

Fluoride. Whether your district adds fluoride is in its water quality report. Some households prefer to reduce it in their drinking water; RO systems can carry an NSF/ANSI 58 fluoride reduction claim. See fluoride removal.

Whatever your concern, check the NSF/ANSI 58 certification and the specific reduction claim on the product's performance data sheet. Certification for one substance says nothing about another.

Installing RO Under a Katy Sink

Once you approve the quote, installation is performed by expert installers working with us. The system sits under the sink with its storage tank; the RO faucet goes in an existing sink hole or a new one in the countertop; and the drain line connects to the sink drain. A line to the refrigerator's ice maker and water dispenser can usually be added. Your quote lists the filter and membrane replacement intervals, and for systems we installed, our service covers filter replacement.